Radek did confirm that multiplayer will not be implemented in the upcoming Silent Hill: Downpour he did mention that Konami are exploring the idea of Silent Hill multiplayer.

“At the moment there will be no multiplayer modes in Silent Hill: Downpour, but Konami are investigating a separate chapter devoted entirely to the multiplayer. We do not know the details but it should be an XBLA title where players have to survive in the town of Silent Hill.”

I am unsure how well the series trademark atmosphere of isolation would translate into a multiplayer setting but obviously we do not know enough at this juncture to see if it could work.